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.t te alu LEANDER R. STREETER, OF CHELSEA, ASSIGNOR TO HIMSELF AND A. B. ELY,`(TRUSTEES,) OF NEWTON, MASSACHUSETTS.

Letters Patent No. 88,229, dated Maz/rch 23, 1869.

IMPROVED DENTISTS FLASK.

The Schedule referred to in these Letters Patent and making part of the came.

Be it known that I, LEANDER R. STREETER, of Ghelsea, in the State of Massachusetts, have discovered or invented a new Mode, or Method of Flasking Artificial Teeth, of which the following, with the drawings, is a full description.

The nature of my invention consists in askiug articial teeth, or the bases of them, by filling the plaster, or material of which the cast is made, around the sides of the mounting and over the teeth, or up to and partially over/the teeth, but not in the back, or concave portion, and afterwards filling the concave part, and taking of that a removable cast.

In the ordinary mode of flaskingthe rubber-plate, (supposing the concave part of what represents the roof of the mouth to be uppermost,) the plaster, or material of which the cast is made, is lled in around the sides ofthe mounting and theteeth, and also over the teeth and in the concave between, so as to make one solid mass of the casting-material.

My mode di'ers in making that part of the cast which fills the concave so as to be separated from the other, and to be removable at pleasure.

The advantages of this mode are, that the material upon which the teeth are mounted is more easily and expeditiously removed,'and the operator is enabled to examine the condition of that part which is excluded from view, before vulcanizing or otherwise treat-ing his.

work, as Well as while it is in progress under the usual mode. He can also add more material, or reduce the quantity already in, if desirable, whereby an exact production of proportions in the base is assured. 'This becomes quite necessary in cases where pyroxyle is used, or such substances as are liable to shrinkage in evaporation or drying.

In the ordinary asking there are used an upper plate,

a lower plate, and an upper and lower section, mouldbox, or rim In the drawings only the upper mould-box is shown,

Figure 1 being a plan viewof that section of the flask containing the upper mould, and

Figure 2, a sectional view from front to rear, with base and teeth.

A A represent the iron shell of the upper section.

G represents the plaster-cast portion of the mould, surrounding the teeth and gums.

B represents the artificial base-plate and gums, and

b, the teeth.

Fig. 1 shows the concave part of the artificial base.

D represents the removable cast,l or removable part In the ordinary asking heretofore, it has not been deemed specially necessary to look in upon the concave of the base, in its process of being formed; and in the making the moulds,- or casts, the parts G and D have been usually united in one solid mass; but in the present and prospective manipulation of artificial bases, it has become desirable and necessary to be able to get at the concavity, in order to make the packing and adherence complete.

What I claim as my invention, i s- The removable cast of the back, or concave part of artificial-teeth mountings,for asking-purposes, substantially as described.

In testimony whereof, I have hereunto subscribed my name.

L. Rr STREETER.

Witnesses:

J. W. PRESTON, M. E. INGALL-s. 

